1. Field of the Invention
The present invention relates to the general field of liquid containers and, more particularly, to control systems for maintaining a liquid level within such containers. More specifically, the present invention relates to a control valve and remote sensor system for regulating the fill level in a swimming pool or similar liquid container.
2. Description of the Prior Art
Modern technology has in many ways simplified the problem of swimming pool upkeep. The availability of more sophisticated chemical treatments, as well as the use of modern skimmers, recirculators, and filtering apparatus, have significantly lessened the manual labor required to maintain sanitary and esthetically pleasing swimming pools. For these technologies to work, however, it is necessary to keep the water level of a swimming pool within a relatively narrow range.
In the past, visual references have been relied upon to maintain the water level within a swimming pool. Upon observing a decrease in the water level, a supply of makeup water would be provided, frequently by manually operating a water control valve. Since even a slightly a low water level can require a large restorative volume, domestic water systems may require several hours before the water level has been restored. This time factor alone makes this task unpleasant, with inattention resulting in over filling, or worse, flooding the surrounding pool area.
The desirability of providing automatic means for maintaining the water level in swimming pools has long been appreciated. Without the need for manual supervision or intervention, the water level of a swimming pool would be maintained within the required maximum and minimum limits.
Systems for monitoring and controlling the water level in a swimming pool or other fluid reservoir are well known to the art. The majority of such systems are not suitable for use in retrofitting in-ground pools, requiring a significant amount of structural modifications to the pool deck and/or the pool walls. In addition to being difficult to install, such conventional water leveling systems are frequently costly to maintain. They often include moving parts that, because of their continual contact with water, are extremely susceptible to damage caused by fatigue corrosion and the accumulation of calcium and other mineral deposits.
Other conventional water leveling systems utilize floats, which are susceptible to corrosion and to failure as a result of the accumulation of calcium and other mineral deposits. Installation of float systems in existing swimming pools also normally requires additional concrete construction (and destruction) as portions of existing pool walls and pool decks are replaced. Until recently, the use of electrical sensors in water level control systems has encountered resistance in implementation due to safety considerations.
In addition to the problems inherent in retrofitting a complex sensor and water control unit adjacent an existing pool, there are also the previously mentioned safety concerns regarding those designs that use electrical communication between the sensor and the control valve unit(s). The need thus exists for a swimming pool water level control system that can be quickly and inexpensively installed and maintained on existing swimming pools. A further advantage would be obtained by utilizing a design that minimizes the opportunities for electrical shock hazards during operation of the water level controller.